The city of Ancient Rome is home to many triumphal arches. They are found practically at every turn, standing proud and strong, proclaiming yet another victorious win for the "eternal city". In fact, there are so many that visitors can spend an entire afternoon touring and pondering these gargantuan trophies. The Arch of Constantine, however, holds a bit more meaning than any of its peers. It marks a great turning point in world history.
In 315 AD, this arch was dedicated to celebrate the emperor Constantine’s victory over his rival and co-emperor, Maxentius, in 312 AD. The night before that crucial military blow, Constantine had a vision of a cross spread across the sky. Proclaiming he owed his victory to Christ, the now sole emperor legalized and installed Christianity as the state religion in gratitude. In no time at all, it seems, the entire Western World turned away from the pagan practices of old and adopted the religion of a once unpopular and fiercely despised group of believers.
So, that is the meaning WITHIN this one arch among many, but to seek any meaning ON the arch proves to be a confusing and senseless task. By the fourth century the Roman Empire had already started to dwindle. As a result, this arch was rather hastily built and quilted together with reliefs, medallions and statuary scavenged from earlier monuments. Any tangible or recognizable decoration found will most likely pertain to the emperor Trajan.